A sudden hippo die-off has sparked fears of an anthrax outbreak in Namibia.

“Over 100 hippos died in the past week. The cause of death is unknown but the signs so far show that it could be anthrax,” Pohamba Shifeta, Namibia’s environment minister, told AFP.

Shocking images out of Bwabwata National Park show dozens of carcasses, flat on their side in rivers with their legs sticking up in the air.

While anthrax is commonly thought of as the white powder capable of biological warfare, the anthrax illness is caused by a bacteria found in soil. This bacteria can lay undetected for decades and is contracted by animals when they graze.

A dead hippo in Bwabwata National Park.YouTube

This wouldn’t be the first time anthrax has killed the region’s hippos.

“This is a situation that we have seen before,” Colgas Sikopo, Namibia’s Director of Parks and Wildlife Management, told New Era Newspaper in Namibia. “It happened in Zambia before and it mainly occurs when the level of the river is so low.”

“Our veterinary services are currently working at the area to determine the cause of death,” Shifeta said. “Once we have the results of the cause of death than we can decide on the way forward.”

Authorities are burning the carcasses — each of which weighs a couple tons — to prevent the spread of disease. However, a number of dead water buffalo have been reported, and park officials are concerned crocodiles could become infected from eating the dead flesh.

Sikopo said the remoteness of the region shouldn’t pose a threat to humans or other wildlife but has warned roughly 5,500 people who live inside Bwabwata not to eat the hippo meat.

If the cause turns out to be anthrax, there’s not much the park can do to prevent a future outbreak.